Code 613.1 Branch Seminar: Dr. Karen Mohr

Department of Earth and Atmospheric Sciences, University at Albany, SUNY
The Guinea Coast is the wettest and most densely vegetated of the climatic zones of West Africa, and one of the least well studied. It experiences a bimodal wet season with a major peak in May-June and a minor peak in September-October. Our work considers long term trends in precipitation and streamflow in this region. The country of Ghana provides an excellent case study for trend analysis, as Ghana spans the length (5 deg) of the region and contains both forest and savanna landscapes. An extensive and complete time series of daily precipitation from 33 rain gauges across Ghana and daily streamflow from 2 un-dammed perennial streams in southern Ghana form the basis of our analysis. We have found a significant and persistent negative trend since 1960 in the precipitation, but more importantly in the streamflow in Ghana. Examination of gridded datasets of cloud top temperatures, winds, and SST suggests that long term changes in monsoon moisture transport to critical MCS development regions such as the Cameroon Highlands may be the first order basis for the trends observed in the surface data.